This invention relates to a photosensitive resin composition, a photosensitive film and a process for preparing a fluorescent pattern using the same, and a phosphor subjected to surface treatment and a process for preparing the same.
In the prior art, as one of flat plate displays, there has been known a plasma display panel (hereinafter referred to as "PDP") which enables multicolor display by providing a phosphor which emits light by plasma discharge.
In such PDP, flat front plate and back plate comprising glass are arranged in parallel with each other and facing to each other, both of the plates are retained at a certain interval by a cell barrier provided therebetween, and PDP has a structure that discharge is effected in a space surrounded with the front plate, the back plate and the cell barrier.
In such a cell, a phosphor is coated for display, and by discharge, the phosphor emits light by UV ray generated from filler gas, and the light can be recognized by an observer.
In the prior art, as a method for forming the phosphor, a method of coating photosensitive resin compositions containing phosphors of the respective colors by a printing method such as screen printing has been attempted and disclosed in Japanese Provisional Patent Publications No. 115027/1989, No. 124929/1989, No. 124930/1989 and No. 155142/1990.
However, the printing method such as screen printing is inferior in formation precision so that there are problems that it is difficult to cope with enlargement of a screen of PDP in the future, and others.
In order to solve these problems, there has been proposed a method of using a photosensitive film containing a phosphor (Japanese Provisional Patent Publication No. 273925/1994).
In the method of using a photosensitive film, a phosphor-containing photosensitive resin layer of a photosensitive film comprising a photosensitive resin layer containing a phosphor and a support film is embedded in the above PDP cell by contact bonding (lamination) under heating, the layer is subjected to imagewise exposure with active light such as UV ray by a photographic method using a negative film, an unexposed portion is removed by a developing solution such as an alkaline aqueous solution, and further unnecessary organic components are removed by calcination to form a phosphor only at a necessary portion.
In the above method of using a photosensitive resin composition containing a phosphor and a photosensitive film, it is necessary to carry out development by a developing solution such as an alkaline aqueous solution so that a copolymer obtained by copolymerizing unsaturated monomers having a carboxyl group or the like is used as a binder resin for dispersion, but a copolymer having a carboxyl group is easily reacted with a phosphor so that the photosensitive resin composition containing a phosphor and the photosensitive film have a drawback that they have poor storage stability such as thickening and gelation.